PRODUCTS

VIPRE

VIPRE (Versatile Internals and Component Program for Reactors; EPRI) is used
for nuclear reactor thermal-hydraulic analysis applications. It was
designed to help evaluate nuclear reactor core safety limits including
minimum departure from nucleate boiling ratio (MDNBR), critical power ratio
(CPR), fuel and clad temperatures, and coolant state in normal operation and
assumed accident conditions. The VIPRE code was developed for the United States
Electric Power Industry under the sponsorship of EPRI.

Zachry operates the
VIPRE User Group (VUG) for member
organizations and EPRI. VUG members fund ongoing code maintenance and
development activities to ensure the long-term code viability.

VIPRE-01

VIPRE-01 is a subchannel analysis tool
designed for general-purpose thermal-hydraulic analysis under normal operating
conditions, operational transients, and events of moderate severity. VIPRE
was developed on the strengths of the various COBRA codes and has been
tailored to the analytic needs of nuclear utilities. It has improved
flexibility of use, upgraded
capabilities, and improved numerical solution schemes. Some of the more
important improvements are an expanded choice of correlations for critical
heat flux, critical power ratio, two-phase flow and heat transfer for reload
and safety analysis, one-pass hot-channel analysis capability, automatic
iteration for set point analysis, subcooled voiding capability, and the
ability to compute bypass channel flow for boiling water reactor (BWR)
applications.

VIPRE-01 predicts the three-dimensional
velocity, pressure, thermal energy fields, and fuel rod temperatures for
single- and two-phase flow in pressurized water reactor (PWR) and boiling
water reactor (BWR) cores. It solves the finite-difference equations for mass,
energy, and momentum conservation for an interconnected array of channels,
assuming incompressible thermally expandable homogeneous flow. The equations
are solved with no time-step or channel size restrictions for stability.
Although the formulation is homogeneous, nonmechanistic models are included
for subcooled boiling and vapor/liquid slip in two-phase flow. VIPRE-01 is a
safety related code and complies with the requirements of 10CFR50 Appendix
B. It has been approved by the United Stated Nuclear Regulatory Commission
for use in performing licensing calculations and is used by a number of
domestic and foreign utilities and fuel vendors.

VIPRE-02

VIPRE-02 is a thermal-hydraulic analysis
code designed to model steady-state conditions and operational transients
in LWR cores and vessels. It uses a two-fluid representation of two-phase
flow, solving conservation equations for mass, momentum and energy for each
phase. This six-equation model is solved implicitly, using a modified
Gauss-Seidel iteration procedure, and has no time-step size limitation for
stability. Models for phase interaction based on flow regime mapping are
provided, using semi-empirical interfacial correlations for heat and mass
transfer, and vapor generation.

For core analysis, VIPRE-02 uses a
subchannel formulation of the conservation equations; for PWR vessel models,
it contains options for a fully three-dimensional representation of the
lower plenum. For core analysis, boundary conditions can be specified using
the inlet flow or the overall core pressure drop. For vessel models, the
hot and cold leg boundaries can be represented using mass sources or pressure
sinks in appropriate modes, with local flow blockages to model vessel
internal structures and the lower plenum and upper head domes. The input
specification is designed to be as flexible as possible, and still remain
relatively user friendly.

Availability

The VIPRE use licenses can be purchased directly from
Zachry. For more information on the VIPRE programs and how they can be obtained,
please contact Mark
Paulsen or Garry Gose at